The aft fuselage section of a variety of aircraft, particularly military transport and cargo aircraft, have a significant upsweep on the underside of the fuselage due to the presence of a main cargo door. The upswept surface typically contributes significant drag to the aircraft, and can be responsible for vortices that form on the underside of the aft fuselage due to the flow of air sweeping around the sides of the fuselage toward the bottom of the fuselage. These vortices typically strengthen as they progress downstream and interact with the vertical tail, thereby generating significant overall drag on the aircraft.
A variety of methods and devices to reduce drag on aircraft have been previously proposed and are known in the art. One exemplary method, known as streamlining, includes the shaping of an airplane to minimize drag. Winglets or other devices positioned at the tips of the wings or on the wings of aircraft are another method for reducing drag on an aircraft. Yet another method for reducing drag on an aircraft includes the use of microgrooves or “riblets” along surface of the fuselage or wings of an aircraft. Furthermore, studies have been reported wherein the use of aft body fairings, aft cavities, vortex strakes, and beavertail strakes have been evaluated for the C-130 airframe.
As fuel costs rise, there is increased importance to reduce the overall drag on the aircraft, as a reduction in drag can significantly reduce operating costs due to of reduced fuel consumption. Thus, there exists a present need for methods and devices operable for reducing drag on aircraft.